Death by Machine Gunning for Renegade Sunbathers

Came across the following amidst my reading for one of my 'ethics of punishment' essays. I'm pretty sure the guy's serious. James, you might like this one :)

"[T]he sheriff of a small town where the courthouse lawn is trespassed upon by five hundred sitting sunbathers need not restrict himself to force proportionate to the wrong of trespassing in order to remove the trespassers. Nor need he restrict himself to the least force sufficient to remove them. He might, for example, be able to carry them off bodily through extreme physical exertion on his part, or by severe depletion fo the town's budget to hire deputies to carry them. But he need not choose these minimally harmful (to the trespassers) options. He may, instead, place a machine gun on the roof of the courthouse, inform the sunbathers that the machine gun is programmed to begin spraying the lawn in five minutes, and leave. [...] Once the trespassers have been warned (the notice principle), and because they have no right to be trespassing in the first place (the wrongful act principle), they have no right to demand proportional response if that is more costly in terms of other values. Moreover, if the sheriff can set up the automatic machine gun, then conceivably it would follow that he could man the machine gun; and if he could man the machine gun, then it would seem to follow that the town council could pass a new trespass ordinance mandating death by machine gunning as the punishment (to become effective at at time when the trespassers have had notice of the new ordinance and a reasonable time to get off the lawn)."

-Lawrence Alexander, 'The Doomsday Machine:
Proportionality, Punishment and Prevention'.